The Participant Interaction Core serves the critical functions of centralizing communications and interactions with participants, monitoring participation rates, and serving as the public face ofthe program project. This Core will contact all participants for continued participation in the series of research studies and will maintain the cohort for the duration ofthe proposed program project. Coordinated efforts In tracking participants current contact information, assignment to specific projects, participation in these projects, and retention in the cohort is vital for the success of the proposed project. The following outline the specific aims of the Core: 1. Maintain IRB approval for the proposed project and coordinate IRB matters across all four projects and the various institutions involved in this program of research; 2. Maintain the existing cohort starting with an initial contact to inform all participants ofthe opportunity for their continued participation in the proposed project; Schedule all data collection visits with participants for each of the four projects; Collect questionnaires from Project 1 participants at four assessments (5-, 6-, 7-, &8-year followups); Collect EMA data from Project 2 participants at three major assessments (5-, 6-, &7-year follow-ups) Collect saliva samples from participants during the 5-year follow-up questionnaire visit (in Year 6) for cotinine (Project 1) and genetic (Project 4) analyses and collect additional samples as required for quality control purposes or flawed Initial samples; Track and locate participants throughout the course of the study; Coordinate the subject flow and timing of participation with special attention to the subset of participants involved in both the Project 2 ecological momentary assessment (EMA) and the Project 3 psychophysiological laboratory (LAB) studies; Coordinate data flow from this core to each project and the Data Management, Measurement, and Statistics (DMMS) Core;and Implement panel maintenance strategies across all 5 years of the longitudinal study.